What type of records can be kept in a Blockchain? Is there any restriction on same?

You can put any type of data in encrypted form in the block. It is recommeneded to not keep large dataset in blockchain.

All sort of records can be maintained ... all it depends upon what purpose you want to use it for

It depends on blockchain. Each blockchain has a specific purpose. Some blockchains are designed for financial transactions, some are for a contract, and some are for IoTs. You can also create your own blockchain. For example, Bitcoin blockchain stores 1 transaction.

However, blockchains are not designed to store large data. Some blockchains are designed for smart contracts such as Ethereum. Means you can store a block of code on the blockchain.